The invention relates to new and useful improvements in subassembly racks with plug-in modules. More particularly, the invention relates to subracks with at least one plug-in module that is provided with a front plate for mounting the module to the subrack.
In conventional subracks, the metallic front plates of plug-in modules generally form a closed, electromagnetically screening front side. The gaps between the individual front plates of the modules are generally bridged with electromagnetic screening by contact spring elements on the front plate. One resulting problem is that the front plates can be slightly displaced between the gaps by the horizontal lateral forces produced because of the contact spring elements. Because of the combined offsets of a number of front plates, one given opening may have too small a width to receive its intended front plate. A module which is to be inserted last between several modules already mounted in place can thus no longer be pushed into the subrack, or can be pushed in only with a risk of damaging the contact spring elements.
A subrack for plug-in modules provided with front plates is known, e.g., from German Patent DE 41 30 355 C1 and from the catalog "europac lab HF, EMC Schroff, D 9/94 7/7 (39600-100)" from the company Schroff GmbH. Longitudinally arranged, equidistant threaded holes for screwing on front plates are provided on two front module rails. The front plates have at least one fastening screw on the top and on the bottom. In addition to the fastening screws, at least one additional centering pin is arranged on the back side of each of the front plates. When a plug-in module is inserted, these centering pins connect into corresponding centering holes arranged in front of the threaded holes, and serve to position the individual front plates in the positions provided at the respective slot on the subrack.
It is disadvantageous that, apart from the fastening screws, centering pins are additionally required to be fitted on the back of the front plates. These centering pins have to be fashioned onto the front plates in their accurate position since, in particular when the front plates are produced by an extrusion process, the centering pins cannot be integrally formed at the same time as the front plates themselves during the production process. One result is a disadvantageously increased outlay in terms of material. In addition, an increased number of production steps is needed for manufacturing the front plates.